Various instruments are commonly employed in surveying, construction, and other applications to measure angles, distances, and elevations. As an example, digital levels are commonly used to provide high-accuracy elevation measurements. Using a digital level, an elevation of an unknown point can be determined relative to the digital level or relative to a known point. A typical leveling procedure involves determining an elevation of the digital level relative to a known point (i.e., a backsight measurement), and determining an elevation of the digital level relative to an unknown point (i.e., a foresight measurement). The difference in elevation between the points can be used to determine the elevation of the unknown point.
At each point the digital level determines a difference in elevation between a horizontal line of sight of the digital level and a measurement point. This is done using a leveling staff. The digital level is used to determine where its horizontal line of sight falls on the leveling staff, and a scale on the leveling staff is used to determine a distance between the horizontal line of sight and the measurement point.
Typical leveling procedures require one person to hold a leveling staff at a measurement point and another person to perform measurements at a digital level. To decrease measurement time, some procedures require two people to hold leveling staffs—one for a backsight measurement and one for a foresight measurement.
While digital levels are commonly used to determine elevation, improved methods are desired to increase measurement accuracy, reduce measurement time, and lower measurement costs.